In the 24th century BC Palermo Stone, the sun hieroglyph is used on the Palermo Piece-(obverse) of the 7-piece Palermo Stone to identify dates, or specific "day-events", ..."day of ...." A few of the King Year-Register's are dates only for example in Row V (of VI rows):

Ra, the Sun-god is Gardiner listed no. C1, of the listed: Anthropomorphic Deities–(more than 20 listed, and other Gardiner unlisted forms used in Ancient Egypt). The God Ra is shown with a sun-disc upon his head – or another common form with the Sun disc, encircled with Uraeus, (the cobra):